The size and capacity of the human brain distinguishes us from all other forms of life on earth, but how well do we really understand the functioning of our brains? Hardtalk speaks to Susan Greenfield, who carved out a reputation as a leader in the study of degenerative brain diseases. Lately though she has focused her attention on the impact of 21st Century digital technologies on brain development. She believes our screen habits could be doing us damage, but is her warning based on sound science?(Photo: Professor Susan Greenfield. BBC copyright)